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A gas blowout may be brought under control by injecting water into the formation through relief wells. By avoiding direct contact between relief well and blowout well, this technique reduces the inflow of gas by creating sufficient backpressure in the formation itself. It guarantees a feasible, successful relief-well injection rate, no matter how large the lifting capacity of the blowout well may be. A constraint condition on relief-well injection pressures is found that ensures killing of the pressures is found that ensures killing of the blowout. The minimum number of relief wells then follows from injection-pressure limitations. The positions of the relief wells are kept arbitrary in positions of the relief wells are kept arbitrary in the analysis, but the results indicate that their landing points should be close to the blowout well and that direct communications with the latter (e.g., by formation fracturing) should be avoided. The analysis yields no information as to shutoff times or cumulative injection requirements. These must be found from a separate study, which could be guided by the results presented in this paper. Introduction Control over a blowout may be gained by any technique that blocks the escaping reservoir fluid either in the wellbore or in the formation. The method most frequently used is wellbore blockage the recapping of a wild well, for example, or the drilling of a relief well to establish direct connection with the wild-well borehole, followed by the injection of heavy mud at a rate greater than the lifting capacity of the blowing well. There are, however, reservoirs in which blowout conditions may become too severe to allow successful surface operations and also reservoirs in which bottom-hole pressures exceed the pressure that could be pressures exceed the pressure that could be balanced by feasible mud injection rates. Complications that rule out surface operations may also arise when the uncontrolled production from one formation "blows in" at another lower-pressure formation. In such cases the only safe and effective remedy may be to inject water into the formation through relief wells deliberately aimed off the wild-well landing point. This restricts the escape of reservoir fluid by a pressure buildup resulting from the flow of water through the formation, and by the continuous narrowing of the passageways open to the escaping reservoir fluid between spreading water-saturated volumes. When all passageways are closed off by the water, the wild well is under "dynamic" control and may produce a large fraction of the water that is being continuously injected it final plugging operation is still necessary to gain permanent control over the well. The termination of permanent control over the well. The termination of relief-well water injection must then be timed carefully, particularly when dealing with an overpressured gas reservoir.We are concerned here with only the reservoir engineering aspects of bringing a well under "dynamic control by continuously injecting water through relief wells. In considering such an operation, the most important matters to be decided are the following:1. The number of relief wells and their location with respect to the blowout well,2. The water injection rate, and3. The total quantity of water injected at shut-off.In the following we present a simple formula for estimating the minimum successful water-injection rate. The minimum number of relief wells required is then obtain from injection pressure limitations. Using this result, it is possible to determine the optimal strategy for locating relief wells. No information is obtained on cumulative injection requirements or shut-off times. This lies beyond the scope of simple analysis; but such a study -which would probably be undertaken on a computer could clearly be shortened by using the results of this paper as a screening tool. ANALYSIS OF A TWO-DIMENSIONAL PROBLEM In formulating the interrelation of the most important parameters governing the conditions for shut-off, we are forced to idealize.We assume that the fluid flow is two-dimensional in a plane homogeneous reservoir of uniformly thick layers. P. 321

Crystals of 4-cyanopyridine-N-oxide crystallize in space groupP21/c (No. 14). There are four molecules per unit cell, witha = 7.88(2),b = 6.10(2),c =11.61(3) A and β =101.4(4) °. Data for 838 unique reflections were recorded using the multiple-film technique and visually estimated intensities. A three-dimensional least-squares refinement of the structure was carried out to a final conventionalR of 0.098. It was found that the molecule was planar, as expected, and that the centrosymmetric pairs were stacked parallel to each other, as viewed down thea-axis. Bond distances and angles are in agreement with those from comparable molecules.

An der Bedienung des offentlichen Personennahverkehrs sind folgende Verkehrstrager beteiligt: a) Die kommunalen und gemischtwirtschaftlichen Verkehrsunternehmen mit ihren Strasenbahnen, Stadtschnellbahnen, Omnibus- und Obusbetrieben. Sie bedienen im wesentlichen den innerstadtisch en Verkehr einschlieslich des Vorort- und Nachbarortverkehrs und sind im Verband offentlicher Verkehrsbetriebe (VOV) zusammengefast. b) Die Bundesbahn mit ihrem Schienen- und Omnisbusverkehr. c) Die nichtbundeseigenen Eisenbahnen, ebenfalls mit Schienen- und Omnibusverkehr. Sie sind im Verband deutscher nichtbundeseigener Eisenbahnen (VDNE) zusammengefast. d) Die Bundespost mit ihren Kraftpostlinien. e) Private Omnibusunternehmer.

A melanotic cell line derived from a malignant melanoma of the golden hamster has retained its ability to produce melanin in vitro. This cell line provides an opportunity for studying the synthesis of melanin under various controlled conditions. The modal chromosome number in this cell line is 68.

Abstract The critical rate is defined is the steady or semi-steady production rate of oil or gas under a drawdown just small enough to prevent water production from an existing layer of bottom water. production from an existing layer of bottom water. Critical rates are determined theoretically for fully perforated wells, assuming a horizontal cap-rock perforated wells, assuming a horizontal cap-rock boundary and allowing the permeability to vary with depth. A generalised 'Girinskii Potential' is defined and used to formulate the three-dimensional free-surface flow of a real gas as a problem in plane flow. A formal analogy with plane incompressible flow is thereby established. As an example, Muskat's results for the flow capacities of small groups of interfering wells are reinterpreted in terms of critical oil or gas production rates. Introduction The occurrence of bottom water in oil or gas reservoirs imposes restrictions on water-free withdrawal rates, since a well will cut water above a certain critical rate. This critical rate is associated with the well-known phenomenon of upconing bottom water. The phenomenon depends essentially on the perforation and intake provisions (position of the tubing-intake level) at the well. To ensure a finite critical rate, these provisions must be such as to allow i water cone to rise a finite distance above an initially flat oil/water contact without immediately reaching the perforated interval or the tubing-intake level inside the well. A steady state can then exist in which the water remains stagnant up to line critical rate and, due to its greater density, hydrostatically balances the pressure gradient in the foil or gas which passes over it towards the well. passes over it towards the well. The assumption of steady-state conditions and of fully segregated fluids separated by a macroscopically sharp interface form the starting point for the majority of investigations concerned with the determination of critical rates. Among these, a further distinction can be drawn between studies dealing with partially penetrating (or partially perforated) wells and those dealing with fully perforated) wells and those dealing with fully penetrating and fully perforated wells, i.e. wells penetrating and fully perforated wells, i.e. wells perforated over the total pay thickness. perforated over the total pay thickness. This article deals with the case of fully perforated wells. perforated wells. The critical production rate of a fully perforated well sited in the centre of a horizontal perforated well sited in the centre of a horizontal circular reservoir, assuming steady incompressible flow, can be determined with the help of Dupuit's famous well-discharge formula upon giving the proper interpretation to the quantities involved. proper interpretation to the quantities involved.

Wir befinden uns gegenwartig in einem Zeitabschnitt, der als dritte Phase einer Entwicklung bezeichnet werden kann, die von den individuellen Verkehrsmitteln ausgehend uber die offentlichen Verkehrsmittel wieder zuruck zu den individuellen Verkehrsmitteln fuhrt. Wahrend in den hochmotorisierten Landern wie den USA bei einem Bestand von 350 Kraftfahrzeugen je 1000 Einwohner diese dritte Phase bereits mehr oder minder abgeschlossen ist, stehen wir in Deutschland bei einem Bestand von 5,8 Mill. Kraftfahrzeugen oder 104 Kfz je 1000 Einwohner mitten in dieser Umschichtung vom offentlichen zum individuellen Verkehr. Abb. 1 zeigt die Entwicklung des Kraftfahrzeugbestandes im Bundesgebiet seit 1946. Wenn auch der Zuwachstrend in den letzten Jahren geringer geworden ist, so wird man doch in 8 bis 10 Jahren mit einer Verdoppelung des jetzigen Kraftfahrzeugbestandes rechnen mussen.